faster spreadsheet exporter based on opensout and other export improvements (#5238)

tests/Export/Package/CellFormatter/ArrayFormatterTest.php

@@ -0,0 +1,42 @@
+<?php
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Tests\Export\Package\CellFormatter;
+
+use App\Export\Package\CellFormatter\ArrayFormatter;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \App\Export\Package\CellFormatter\ArrayFormatter
+ */
+class ArrayFormatterTest extends TestCase
+{
+    public function testFormatValueReturnsCommaSeparatedStringForArray(): void
+    {
+        $formatter = new ArrayFormatter();
+        $result = $formatter->formatValue(['one', 'two', 'three']);
+        self::assertEquals('one, two, three', $result);
+    }
+
+    public function testFormatValueThrowsExceptionForNonArray(): void
+    {
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('Only arrays are supported');
+
+        $formatter = new ArrayFormatter();
+        $formatter->formatValue('not an array');
+    }
+
+    public function testFormatValueReturnsEmptyStringForEmptyArray(): void
+    {
+        $formatter = new ArrayFormatter();
+        $result = $formatter->formatValue([]);
+        self::assertEquals('', $result);
+    }
+}